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Additional file 2. Graph of the filtered x-ray spectrum used for the in vitro experimentation.

Additional file 3. Graph of energy against DEF for the range of energies in the x-ray spectrum used for in vitro experimentation.

Additional file 3. Graph of energy against DEF for the range of energies in the x-ray spectrum used for in vitro experimentation.

Nuclear medicine is used to diagnose and treat a number of disorders and diseases and is an essential part of a hospital’s clinical toolkit. Diagnostic nuclear medicine utilises radioactive isotopes which emit either gamma-rays or positrons. Therapeutic nuclear medicine involves the use of radioactive isotopes which emit high-energy electrons or alpha particles. Four terbium isotopes (149Tb, 152Tb, 155Tb and 161Tb) have been shown to possess physical and chemical properties suitable for a wide range of therapeutic and diagnostic applications in nuclear medicine1. If a diagnostic terbium isotope is used in combination with a therapeutic terbium isotope (e.g. 155Tb and 161Tb) it would give a theranostic pair with identical chemical properties. This is a particularly promising characteristic as it facilitates the use of personalised medicine. Currently, the main obstacle preventing these terbium isotopes reaching clinical practice is their production and subsequent chemical separation in the quantities required for preclinical and clinical trials. In all cases, terbium needs to be isolated from lanthanide impurities and this is a challenging task due to the very similar chemical properties of neighbouring lanthanides. The aim of this study is to develop an efficient and robust method to purify terbium from other lanthanides2. The separation of terbium from other lanthanide elements was studied on LN® resin (Triskem International), an extraction chromatography resin. Stable element standards were used for method development and inductively coupled plasma mass spectrometry (ICP-MS) used to quantify the quality of the achieved separation. Both batch and column studies were conducted to identify the optimal separation conditions. The terbium solutions produced using the derived method were of a purity (>95% terbium) that is suitable for use in preclinical and clinical study. 1 C. Muller et al., J. Nucl. Med., 2012, 53, 1951–1959. 2 B. Webster et al., Sci. Rep., 2019, 9, 10884.

A number of industries generate by-products containing naturally occurring radioactive material (NORM). Such materials must be characterised prior to re-use, for example, in building materials or for sentencing as waste. Reference materials, reflecting the variety of matrices and principal radionuclides encountered, are required to validate radioanalytical methods for accurate measurement and to demonstrate compliance. Currently, the only certified reference material available is a phosphogypsum matrix, distributed by the IAEA, in connection with phosphoric acid production. A blast furnace slag reference material has been developed for use in the steel and cement production industries. The results of an inter-laboratory comparison exercise, involving 23 laboratories across 14 countries are summarised, focussing on measurement of 40K, 226Ra and 232Th activity concentrations. The work addresses the need for additional NORM reference materials and provides an infrastructure for future inter-comparison exercises. A second material from an oil pipeline has been characterised in preparation for the next exercise. Underpinning the accurate measurement of reference materials, and all applications of nuclear science, is the accuracy and precision of nuclear decay data. In some cases, the data are outdated and/or significant uncertainties remain, which limits the measurement precision achievable. This project presents a methodology for atom counting of long-lived radionuclides using isotope dilution mass spectrometry combined with absolute decay counting methods for measurement of half-lives. The methodology has been applied to 238U, for which limited half-life measurements exist, most recently from 1971. The methodology developed will be applicable to other naturally occurring radionuclides that suffer from similar decay data limitations, including 232Th.

The main objective of this investigation was to find mosquito larvicidal secondary metabolites from a basidiomycete – Stereum species (JO5289) – against Aedes aegypti . The Stereum species (JO5289) was collected in July 2005 from undisturbed habitat in Londiani forest in Rift Valley province, Kenya. Extracellular crude extracts from Stereum species (JO5289) produced strong activity against A. aegypti larvae. Purification of the crude extracts targeting larvicidal activity using chromatography gave three active compounds namely; tyrosol, 3-methoxy-5-methyl-1,2-benzenediol and 2-hydroxy-4-(4-hydroxychroman- 7yl) but-3-enal. The chemical structures of the compounds were determined using the nuclear magnetic resonance (NMR) spectral data and comparison with literature values. When tested for larvicidal activity, the LC 50 for the three compounds were 26.7, 17.3 and 14.5 ppm, respectively, while LC 90 were 85.3, 83.5 and 82.9 ppm, respectively, after 24 h of exposure. These compounds have been produced from cultures of a Stereum species and reported to have mosquito larvicidal activity for the first time. Key words: Basidiomycete, Stereum species, Aedes aegypti , extracellular metabolites and larvicidal.